Our objective is to develop a regimen for immunotherapy of tumors using RNA-rich extracts from syngeneic or xenogeneic animals immunized to the tumor. The rationale of immunotherapy is to convert syngeneic nonsensitive peritoneal exudate cells (NS-PEC) with "tumor-immune" RNA extracts so that they become immunologically reactive to the tumor specific antigen (TSAg), which is then added to specifically stimulate the converted cells. Our proposal is based on experiments with a transplantable diethyl-nitrosamine-induced hepatoma in strain-2 guinea pigs. We already found that when syngeneic NS-PEC, syngeneic or xenogeneic "tumor immune" RNA, and TSAg are injected s.c. 5-days after the injection of a uniformly lethal dose of line-10 tumor cells, complete tumor regression of the intradermally growing tumor was observed in all 24 strain-2 guinea pigs treated. Omission of either the NS-PEC, RNA or TSAg from this regimen was ineffective in tumor abrogation. Since all animals were treated after metatases are frequently known to occur, the long-term tumor-free survival of these animals suggested that the "RNA therapy regimen" may induce a systemic immunity against the tumor. Our specific aims now are as follows: 1) to determine the optimal conditions for abrogation of tumors established by i.d. injection of uniformly lethal doses of diethylnitrosamine-induced hepatoma cells; 2) to assess tumor immunity in guinea pigs cured of tumor; 3) to assess the effect of local therapy on metastases using tumor cells injected at a second or multiple sites as a model; 4) to compare the effectiveness of "tumor immune" RNA by reciprocal experiments with line-10 and another line; 5) to explore RNA therapy in combination with other methods, e.g., anti-fibrinopeptide E, BCG, or chemotherapy; 6) to extend the immunotherapy model to other tumors and other species; 7) to isolate and characterize the active RNA. The methods involve the preparation of tumor immune RNA rich extracts from a variety of animals, the preparation of TSAg from a variety of tumors, histological studies of treated sites, and the maintenance of tumor lines. This immunotherapy model appears to be better than BCG for this tumor. Its requirements and limitations need to be fully characterized.